Open Sources: Voices from the Open Source Revolution

This book is an excellent compendium of essays by the major open source leaders, including Torvalds, Stallman, Raymond, O'Reilly, and others. While the book is now a bit dated, it is definitely worth reading to get a feel for the birth of the Open Revolution and the thoughts of its founders. A free, online version of this book is available from O'Reilly Books.